One way of identifying or comparing compositions of materials is by comparing graphs showing the reflectivity of the materials to energy in a given part of the electromagnetic spectrum. Visual or numerical comparison is made of the spectral width and placement of peaks within the given portion of the spectrum. Both the mid-infrared and near-infrared ranges are commonly used, but each of those ranges is problematic. In the near-infrared range, peaks for different materials are not as easily distinguished as in the remainder of the infrared range, a lack of resolution that introduces interpretive errors into the measurements. However, in the mid-infrared range measurements are more prone to include artifacts, errors that are introduced during the preparation of the sample which must be measured in a thin layer and under carefully standardized conditions. In particular, measurements in the mid-infrared range are highly sensitive to common sample handling problems and subtle variations in the physical condition of the sample.